Project Summary Head injury is a major public health issue. In the United States alone, traumatic brain injury (TBI) causes 235,000 hospital visits, each year. The bulk of these TBI are categorized as mild (concussion; mTBI). It is assumed that after a few months patients gradually return to their premorbid states including the assumption of full cognitive recovery. However, there is a fundamental gap in knowledge as to whether people return to neurotypical levels of performance post-injury, or whether there are lasting cognitive consequences of mTBI. In the current environment, there is no prolonged monitoring and no intervention to track cognitive performance beyond the several week recovery period. This proposal investigates whether people with a history of mTBI return to neurotypical levels of performance on working memory tasks and evaluates neural connectivity to test whether performance is related to neural differences. Working memory is selected as a practical selection because it is an important executive function that could be impacted by a heterogeneous injury such as mTBI. In other words, damage to many parts of the brain could contribute to working memory impairment, thus it would be sensitive to different individual?s mTBI. The populations tested here include chronic mTBI and those in the subacute stage of mTBI recovery. Over both the F99 and K00 phases of the training grant I propose to study both of these mTBI populations using a variety of methodologies to advance my training, including behavioral, HD-EEG, resting state EEG, fMRI, DTI, and neuropsychological tests. In the F99-phase of this proposal (Aim 2), I will gain training in advanced analysis skills and develop additional collaborations with extramural colleagues. I will develop technical skills associated with coding experiments and I will subject data to statistical approaches beyond my current understanding. These skills will allow me to better understand the temporal changes that unfold during cognitive recovery in subacute mTBI. I will also study the cognitive and neural deficits associated with a longer duration since injury in the chronic mTBI population. During the K00- phase of this proposal (Aim 3), I plan on continuing to investigate the extent of enduring cognitive changes associated with mild and moderate TBI. The extension will be to use different neural measures such as resting state fMRI and DTI to assess how neural networks are impacted following injury and which types of changes are more predictive of behavioral performance. The short-term goal of the proposed work is to understand the cognitive and neural consequences associated with mild and moderate forms of TBI. This long-term goal of mine, as a future independent researcher, will be to develop and refine interventions to address cognitive performance in the mTBI and TBI populations. This grant would allow me to make significant progress toward my long-term goal.